Treatment of threads or fabrics containing cellulose acetate



Patented Oct. 14, 1930 UNITED STATES PATENT OFFICE GUILLAUME LARD Y, OE ROUSSILLON, FRANCE, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO DU PONT RAYON COMPANY, OF NEW YORK, N. Y., A CORPORATION 013 DELA- WARE TREATlIENT OI THREADS OR FABRICS CONTAINING CELLULOSE ACETATE I No Drawing. Application filed June 6: 1928, Serial No. 283,467, and in Great Britain June 23, 1927.

This invention relates to the treatment .of threads of spun filaments of cellulose acetate or fabrics containing them and more especially to a process for impartin to the cellulose acetate materials a woo ly appearance and feel and/or special appearance.

Herzog in Kunstofie (May 1, 1913) has disclosed that when fibers of cellulose acetate are subjected to damp heat at high temperature, they swell and acquire or assume an opaque, milky appearance. This phenomenon has also been observed when fabrics containing cellulose acetate fibers alone or mixed with other textile fibers are subjected to a desizing or dyeing operation wherein very hot aqueousbaths containing soaps or acids, depending on the result desired to be attained by said operation, were employed. Various processes have been proposed to obtain this woolly appearance at will. In certain processes the cellulose acetate material was subjected to the action of boiling. (or nearly boiling) aqueous solutions of organic acids (especially formic and acetic) of relatively high concentrations (8'%15%). Usually the highest concentration was used since it appeared to give the:

most intenseeflects. None of the proposed methods utilized mineral acids. In fact, the

use of'mineral acids was considered inoperative or disadvantageous and their use warned against.

I have found that very dilute boiling solutions of mineral or organic acids are effective dulling agents for cellulose acetate fibers or threads. I haye'also found that the appearance of the dulled thread is dependent on the acid used and that Various acids 've various results. These results are set orth in the following table Concen- Percent AOldS tration age Appearance Hydrochloric.. N/lO 0.365 Mother-of-pearl dull woolly. Phosphoric N/ 0. 066 Woolly. Arsenious N/lO 0. 33 Mother-of-pearl. Boric N/lO 0.21 Dull mother-qf-pearl cottony. Benzoic N/50 0. 244 Very markeddull. Salicylic N/100 0. 138 Very marked dull.

Nap h t h ale n e N/lOO 0. 208 Extremely marked woolly apsulphonic pearance and feel.

Anthranilic N/lOO' 0. 137 Slightly less marked woolly appearance and feel than w th naphthalene sulphonic acid. Pyrogallic N/20 0.21 Wtoolly feel with fawn colora- The use of very dilute boiling acid soluare hydrochloric,

tions per se, however, has a serious disadvantage. Oellulose acetate fibers when subjected to a dilute boiling acid solution show a decrease in their serimetrical qualities. In certain cases this effect renders the threads unfit for use. I have, however, found that I can overcome this defect by subjecting the cellulose acetate fibers to a treatment with an aqueoussolution containing a chloride prior to the treatment with the dilute acids.

It is therefore an object of this invention to provide a method for impartin a rapid dulling action on cellulose acetate tiers with dilute acid solutions without affecting the qualities of the cellulose acetate fibers.

Another object of this invention is to provide a method comprising treating the cellulose acetate fibers with anaqueous solution containing a chloride preferably of light metal such as magnesium, calcium or lithium prior to the treatment with the hot dilute acid solutions.

Other objects will become apparent from the following description and appended claims.

According to this invention, I subject the cellulose acetate fibers, threads or yarns or fabrics containing said fibers to an aqueous solution containing a chloride and then subject the treated materials to the action of a boiling solution dilute acid.

The chlorides which I have found to give very satisfactory results are the chlorides of calcium, magnesium and lithium. These chlorides may be used in varying concentrations. I, however, prefer to use a 10%3 0% concentration, since this concentration glves most regular and uniform results. The cellulose acetate material is treated with the aqueous chloride solutions at ordinary tempera-- ture from 2 to 24; hours depending on the degree of torsion of the thread or the tightness of the weave of the fabric. The hlgher the degree of torsion or the tighter the weave of the fabric the longer must be the subjectlon to the aqueous chloride bath. If the cellulose acetate were at this stage of the process washed without tension free from the chloride, it would possess the characteristic glossy appearance and feel of the original fabric.

The acids which I may use in the process phosphoric, arsenious, boric, benzoic, salicylic,

naphthalene-sulhonic, anthranilic, pyrogallic and'the like. he concentration of the acid should not (ex ceed 1/10 of the normal concentration and when the cellulose acetate is subjected there- 5 to, it should be at its boiling temperature.

\ As stated, the concentration of the acid should not exceed N/ 10. This is true with respect to mineral, inorganic or organic acids.

owever,when I employ organic acids in my process, the concentration thereof may be less thanthat used with mineral acids. I have "found that a concentration of N/ 100, or even less in the case of organic acids, produces sat isfactory results. The cellulose acetate may be subjected to the boiling aqueous acid solutions for various times. I have found that 1 to 20 minutes is generally sufficient to accom plish the desired results.

Hydrochloric acid has a detrimental influence oncotton and viscose fibers and accord-' ingly it should not be used in treating fabrics containing such fibers.

The method and apparatus employed in the above treatment may be of any well known type.

The process will become clearer and better understood from the following specific examples. I

Ewam le [.A fabric with a satin weave comprisln a cellulose acetate silk warp and a cotton we t is, after desizing, immersed for 12 hours in a 30% aqueous solution of calci um chloride. After the removal of the. excess material the fabric is treated for 20 minutes in a boiling N/lO boric acid solution. After this treatment the fabric is rinsed and dried. The fabric treated in this manner has .acquired a peculiar dull mother-of-pearl-like appearance and has not sacrified any of its desirable properties.

Example II..A velvet with an acetate silk pile is immersed for 4 hours in a 20% solution of calcium chloride. It is then immersed in. a

boiling N/ benzoic acid solution for 10 minutes. The velvet so treated has a dull aparance and this dullness persists even after yeing by any of the usual methods and dyes for mixed fabrics containing cellulose acetate silks.

Ewample III.A crepe havin natural silk .warp and acetate silk weft, is, a ter desizing, immersed for 24 hours in a 10% calcium chloride solution. After the removal of the excess of calcium chloride solution it is treated for 15 minutes with a' boiling N /100 betanaphthalene-sulphonic acid solution. A crepe so treated acquires a very regular dull appearance and has an extremely supple andwoolly feel. It can be dyed by'any of the usual methods.

'Ewamp'le lV.-A skein of cellulose acetate is immersed for 5 hours inan a ueous 10% calcium chloride solution. After t e removal of the excess solution it iskept in contact with a boiling N /10 hydrochloric acid so- 4 7 lution for 20 minutes. This treatment imparts to the skein a dull mother-of-pearl appearance. The cellulose acetate fibers have not sacrificed any of their desirable qualities. Their strength and dyeing properties remain unimpaired.

Example V.One kilogram of acetate silk is immersed for 8 hours in an aqueous solution of 20% calcium chloride. The excess solution is removed in air'by any of the usual and well known methods. After this treat-' ment it is immersed for 15 minutes in a boiling N /20 solution of pyrogallic acid. After this treatment it is washed or rinsed with water. Finally after the removal of the excess water, it is dried in a stream of hot air at approximately 70 C. Silk treated in this manner becomes matt and acquires a fawn shade similar to the wool of the angora goat or similar to camels hair.

Example Vl.-A fabric having a linen weave, the warp and weft being cellulose acetate, is immersed for .3 hours in an aqueous solution of 10% calcium chloride. After the excess solution is removed, and after washing, the fabric is dipped for 10 minutes in a boiling N/50 solution of pyrogallic acid. After this treatment the excess materials are removed by any of the well known methods and the treated fabric is dried in the cold air. A fabric so treated has a slightly matt appearance. It has also acquired the a pearance. of a cloth woven with raw sil hke tussah silk. By the above process, dulling effects with good intensity and perfect regularity are imparted to the threads, yarns or fabrics. The threads, yarns or fabrics acquire a most pleasing appearance and do not sacrifice any of their desirable quallties, es-

pecially their susceptibility of elongation.

N o de-acetylation of the fibers takes place during the treatment. The fibers reta n, with respect to dyeing, the characterlstlcs and qualities of the original cellulose acetate.

The process, furthermore, is especially important from an economical polnt of new. Apart from the fact that a smaller amount of material is used, due-to the fact that the acid bath is very dilute,.the loss of the acid by evaporation and the emanations of the It is furthermore obvious that acids are reduced to a minimum. Also the fabrics with an aqueous solution containing calcium chloride, and subsequently subjecting said treated material to a boiling dilute acid solution, the concentration of said acid not exceeding N/lO.

2. A process for obtaining matt or woolly effects on threads or spun filaments of cellulose acetate or fabrics containing them which comprises treating said materials with an aqueous solution containing 10%-30% calcium chloride, and subjecting said treated material to a boiling dilute aqueous acid solution, the concentration of said acid not exceeding N/lO.

3. A process for obtaining matt or woolly effects on threads or spun filaments of cellulose acetate or fabrics containing them which comprises treating said materials with an aqueous solution containing 1'0%30% calcium chloride at room temperature, and subjecting said treated material to a boiling dilute aqueousacid solution, the concentration of said acid not exceeding N/lO.

4. A process for obtaining matt or woolly effects on threads or spun filaments of cellulose acetate or fabrics containing them which comprises treating said materials with an aqueous solution containing 10%-30% calcium chloride, and subjecting said treated material to a boiling dilute aqueous acid solution for 1-2O minutes, the concentration of said acid not exceedin N/ 1 0.

5. A process for 0 taining a matt and curly appearance on.threads or spun filaments ofcellulose acetate or fabrics containing them with a marked increase in volume and an extremely woolly touch which comprises treating said materials with an aqueous solution containing calcium chloride and subjecting said treated materials to the action of a boiling aqueous solution of naphthalene-sulphonic acid, said acid solution having a concentration not exceeding N/lO.

6. A process for obtaining matt or woolly effects on threads or spun filaments of cellulose acetate or fabrics which contain them which comprises treating said threads or fabrics with an aqueous solution containing a chloride of a light metal, and subsequently subjecting said treated material to a boiling dilute acid solution, the concentration of said acid not exceeding N/lO.

7. A process for obtaining matt or woolly effects on threads or spun filaments of cellulose acetate or fabrics which contain them which comprises treating said threads or fab-- rics with an aqueous solution containing a chloride of a light metal at ordinary temperature, and subsequently subjecting said treated material to a boiling dilute acid solution, the concentration of said acid not exceeding N/lO. v

8. A process for obtainin matt or woolly .effects on threads or spun fi aments of cellulose acetate or fabrics which contain them which comprises treating said threads or fabrics with a solution containing a chloride of a light ,metal, and subsequently subjecting said treated material to a hot dilute acid solution, the concentration of said acid not exceeding N/ 10.

9. A process for obtaining matt orwoolly effects on threads or spun filaments of cellulose acetate or fabrics which contain them which comprises treating said threads or fabrics with a solution containing a chloride of a light metal, and subsequently subjecting said treated material to a hot dilute or anic acid solution, the concentration of sai acid not exceeding N/lO.

10. A process of obtaining matt or woolly effects on threads or spun filaments of cellulose acetate or fabrics which contain them which comprises treating said threads or fabrics with an aqueous solution containing cal- A,

cium chloride, and subsequently subjecting said treated material to a hot dilute naphthalene sulphonic acid solution, the concentration of said acid not exceeding N/lO.

11. A process for obtaining matt or woolly effects on threads or spun filaments of cellulose acetate or fabrics which contain them which comprises treating said threads or fabrics with a 10% solution of calcium chloride, and subsequentl subjecting said treated material to a'hot ilute naphthalene sulphonic acid solution, the concentration of said acid not exceeding N/lO.

12. A process for obtaining matt or woolly effects on threads or spun filaments of cellulose acetate or fabrics which contain them which comprises treating said threads or fabrics with a 10% solution of calcium chloride, and subsequently subjecting said treated material to a hot dilute B-naphthalene sul-- phonic. acid solution, the concentration of said acid not exceeding N/lO.

' 13. A process for obtaining matt or woolly effects on threads or spun filaments of cellulose acetate or fabrics which'contain them which comprises treating said threads or fab.- rics with a 10% solution of calcium chloride, and subsequently subjecting said treated material to a hot dilute B-naphthalene sulphonic acid solution, the concentration of said acid being N/lOO.

14. Articles of manufacture comprising threads or spun filaments of cellulose acetate or fabrics containing the same having substantially the properties and characteristics as those produced when said materials are treated with a light metal chloride solution, and subsequently with a hot acid solution, the concentration of said acid not exceeding N 10.

15. Articles of manufacture comprising threads or spun filaments of cellulose acetate or fabrics containing the same having substantially the properties and characteristics as those produced when said materials are treated with a solution containing 10% to 30% of calcium chloride, and subsequently with a hot acid solution, the concentration of said acid not exceeding N/ 10.

16. A process of obtaining a matt appearance on threads or spun filaments of cellulose acetate or fabrics which contain them which comprises treating said materials with an aqueous solution containing a chloride of a light metal and then subjecting the treated material to a hot dilute benzoic acid solution, the concentration of said acid not exceeding N 10.

17. A process of obtaining a matt a pearance on threads or spun filaments of ce lulose acetate or fabrics which contain them which comprises treating said materials with an aqueous solution containing calcium chloride and then subjecting the treated material to a boiling dilute benzoic acid solution, the concentration of said acid not exceeding N/lO.

18. A process of obtaining a mother-ofpearl appearance on threads or spun filaments of cellulose acetate or fabrics which contain them which comprises treating said materials with an aqueous solution containing a chloride of a li ht metal and subjecting said treated materia to the action of a hot dilute solution of hydrochloric acid, the concentration of said acid not exceeding N/lO.

19. A process of obtaining a mother-ofpearl appearance on threads or spun filaments of cellulose acetate or fabrics which contain them which comprises treating said materials with an aqueous solution containing calcium chloride and subjectin said treated material to the action of a boi ing dilute solution of hydrochloric acid, the concentration of said acid not exceeding N 10.

- In testimony whereof, I have afiixed my signature to this specification.

GULLLAUME LARDY. 

